GENETICALLY-ENGINEERED PIG ORGAN TRANSPLANTATION IN BABOONS: IMMUNOLOGICAL AND FUNCTIONAL STUDIES CORE B: IMMUNOBIOLOGY CORE (Core Lead: Hidetaka Hara MD, PhD) SUMMARY/ABSTRACT The Immunobiology Core (Core B), which has many advanced tools, will provide a service to all 3 Projects (kidney, liver, heart) by carrying out all of the immunoassays required in each study. Core B will standardize all of the assays that will be carried out between the two centers (UAB and UMB). In this way, the results of studies in the kidney, liver, and heart models can be compared in the absence of any difference in the methods used. The Core will monitor the immune status of the transplant recipients and will attempt to determine the mechanisms of acceptance or rejection of the xenografts. Core B will apply many tools of molecular and cellular immunological assays to investigate both the innate and adaptive immune responses to the genetically-engineered pig grafts. Specifically, we will assess the contributions of the genetic engineering of the organ-source pigs and the exogenous immunosuppressive therapy to overcome the immune barriers to a xenograft, with the aim of providing insight into the mechanisms of xenograft acceptance or rejection. Core B will coordinate its findings relating to the immune status of the recipients of the xenografts with those relating to the histopathology of the grafts provided by Core C. We hypothesize that the investigation of the systemic immune response, and of the local features (in the graft) associated with that immune response, will help determine the mechanism of xenograft injury and of local immune regulation (e.g., peripheral tolerance).